It will see the pay of first-year apprentices who have completed Year 12 increase to $398.50 per week.

The pay of second-year apprentices, who have also completed Year 12, will rise to 65 per cent of the adult wage.

We know that there are many apprentices who are failing to complete their apprenticeship because of the low rates of pay

Andrew Dettmer, AMWU

Apprentices will also be entitled to payment for excess travel costs for training and reimbursement for fees and text books.

The Fair Work Commission says the pay rise is beneficial for apprentices and employees.

"We consider that such a differential is appropriate in setting a fair and relevant minimum safety net for apprentices and would recognise the benefits of having better-educated and potentially more productive young people entering apprenticeships," the commission said in a statement.

But Andrew Dettmer from the AMWU says those already in the system will be left on the current rates of pay up to the end of their apprenticeship.

"We know that there are many apprentices who are failing to complete their apprenticeship because of the low rates of pay and that was the evidence that we led and wasn't contradicted," he said.

"We know therefore that by only applying to prospective apprentices, that we're going to have a situation where the existing apprentices won't see their rates of pay addressed."

He says the union would use direct pay negotiations with employers to get the increase passed on to existing apprentices and trainees.